The present invention concerns methods for enhancing the development of oviparous species such as birds, reptiles and fish by the in ovo administration of nutrients, enteric modulators, or both.
A major change occurs in the source of nutrients in the post-hatch bird as the yolk is replaced with an exogenous diet. The hatchling must switch from a yolk nutrient-based diet (mainly fats) to a solid feed diet (mainly carbohydrates and proteins). Birds hatch with an immature gastrointestinal tract-indeed, with the yolk sac still attached. After hatch the gastrointestinal tract undergoes rapid morphological, biochemical and cellular development in order to assimilate ingested nutrients. Since the intestine is instrumental in supplying the precursors for growth, its development plays an important role in the animal""s ultimate ability to grow, gain weight, utilize dietary nutrients, and resist enteric disease pathogens.
All oviparous species hatch with an underdeveloped capacity to digest dietary constituents, thus hatchling growth and enteric disease resistance is greatly suppressed. Post-hatch development of this digestive capacity is facilitated by exposure of enteric tissue to dietary constituents, but this is often compromised by various environmental factors that act upon the hatchling. There is a need to facilitate the digestive capacity before hatch because there are little environmental factors that can compromise enteric development during incubation. Moreover, because shorter incubation time and weak hatchlings are observed in a number of situations, such as when eggs are produced by young hens, there is a need for new ways to stimulate the enteric development and growth of birds after hatch.
Accordingly, an object of the present invention is to provide a method of facilitating the enteric development and/or growth of birds, including both food and non-food animals such as endangered species, after hatch.
In view of the foregoing, a first aspect of the present invention is a method of facilitating the growth of an animal such as a bird after hatch, comprising feeding to an animal in ovo (preferably by administration into the amnioic fluid), a nutrient composition in an amount effective to facilitate the growth of said bird after hatch. The nutrient composition preferably comprises at least one nutrient selected from the group consisting of carbohydrates, proteins, peptides, and amino acids, and may also include minerals, vitamins, and other nutriceuticals.
A second aspect of the present invention is a method of facilitating the growth of an animal such as a bird after hatch, comprising administering to the animal in ovo an enteric modulator in an amount effective to facilitate the enteric development before hatch and/or growth of the animal after hatch.
A third aspect of the present invention is a method of facilitating the growth of a bird after hatch, comprising concurrently administering to a bird in ovo (i) a nutrient composition and (ii) an enteric modulator. The nutrient composition and the enteric modulator are together administered in an amount effective to facilitate the enteric development before hatch and/or growth of the bird after hatch, and preferably to synergistically facilitate the growth of the bird after hatch. The nutrient composition is preferably administered by feeding, and the nutrient composition preferably comprises at least one nutrient selected from the group consisting of carbohydrates, proteins, peptides, and amino acids, and may also include minerals, vitamins, and nutriceuticals.
Examples of substances which have been introduced into embryonated poultry eggs via in ovo injection include live culture vaccines, antibiotics, vitamins, and competitive exclusion media (e.g., a live replicating organism) (see generally U.S. Pat. No. 6,244,214 to Hebrank). Specific examples of treatment substances are described in U.S. Pat. No. 4,458,630 to Sharma et al, and U.S. Pat. No. 5,028,421 to Fredericksen et al. See also U.S. Pat. No. 4,458,630 to Sharma et al., U.S. Pat. No. 4,681,063 to Hebrank, and U.S. Pat. No. 5,158,038 to Sheeks et al. Insofar as the applicants are aware, the administration of nutrients or enteric modulators to birds in ovo into the amnionic fluid has neither been suggested nor disclosed. Because the hatchling orally consumes the amnionic fluid prior to hatching, administration of nutrients or enteric modulators into the embryonic amnion is fundamentally feeding the embryo an external diet prior to hatching; thus the term xe2x80x9cin ovo feedingxe2x80x9d is the preferred descriptor of this technology.
In ovo feeding, therefore, involves the administration into the embryonic amnion a solution or suspension of nutrients together with other natural compounds that modulate enteric development to improve the hatchling""s nutritional status during the transition from embryonic nutrition to diet digestive competence. Optimal nutritional status during this critical period is crucial for the development of the digestive, skeletal, muscular, and immune systems, and it helps normalize homeostatic hormone status so important to sustain balanced metabolism. The novel aspect of this technology is the in ovo delivery of nutrients and enteric modulators into the amnion of the embryo during the last quarter of embryonic development. This methodology is necessary because the amnion is orally swallowed by the embryo, and consequently the in ovo administered feeding solution/suspension is ingested by the embryo and is presented to enteric tissues, such as enterocytes and other cells of the gut mucosal membrane.
Preferably the in ovo feeding techniques of the present invention serve to enhance the enteric development of late term embryos and hatchlings, and improves the body weights (and preferably the survival rates and disease resistance) of hatchlings, both at the time of hatch and after a period of time after hatch (e.g., two or three weeks).
A further aspect of the present invention is the use of a nutrient and the use of an enteric modulator (either separately or in combination) for the preparation of a composition for the in ovo feeding of an animal subject as described herein.
The present invention is explained in greater detail in the specification set forth below and the drawings herein.